Non-corrosive lubricating compositions



3,108,071 NGN-CORRGSIVE LUBRICATING CONHQSITIQNS Robert J. Harher, Terre Haute, Ind, assignor to Commercial Solvents Corporation, New York, N.Y., a corporation of Maryland No Drawing. Filed May 8, 1959, fier. No. 811,891 7 Claims. (Cl. 25247.5)

My invention relates to non-corrosive lubricating compositions. More particularly, it relates to non-corrosive lubricating compositions comprising essentially a lubri- Where R is a member selected from the group consisting of the radicals benzyl and cyclohexyl, aliphatic hydrocarbons containing up to and including 20 carbon atoms and aliphatic alcohols containing up to and including 4 carbon atoms.

It is well known to the art that substantially all hydrocarbon lubricating oils are susceptible to harmful oxidation. The degree of susceptibility depends on the process used for refinement and the degree to which readily oxidizable substances are removed. A satisfactory refined lubricating oil can be obtained by refining a crude hydrocarbon oil in the presence of sulfuric acid and treating the refined oil with various compositions; among them silica gel, natural clay, activated charcoal and AlCl Such a lubricating oil, however, tends to form acidic substances when subjected to oxidizing conditions. These acidic substances are undesirable and have acorrosive effect upon the metals with which the lubricating oil comes in contact during lubrication. This factor not only shortens the useful life of the lubricating composition, but causes the deterioration of much expensive machinery.

Generally, a suitable non-corrosive lubricating composition minimizes the corrosive effect of oxidation products upon the metals with which a lubricant comes in contact during lubrication and forms a continuous film upon metal surfaces which Will resist breakage over extended periods of time even though continuously exposed to the oxidation products normally formed in a lubricating oil.

I have now discovered that a highly satisfactory noncorrosive lubricant which will form a protective film 'on metal surfaces, said film being resistant to breakage by oxidation products over an extended period of time, can be prepared by adding to a common lubricating oil a substituted imidazolidinethicne having the following structural formula:

where R is a member selected from the group consisting 3, l 3,71 Patented Oct. 22, 1963 of the radicals benzyl and cyclohexyl, aliphatic hydrocarbons containing up to and including 20 carbon atoms and aliphatic alcohols containing up to and including 4 carbon atoms. Examples of the above-described substituted imidazolidinethiones which are operative in my invention include l-(hydroxy t butyl) 4,4-dimethyl-2- imidazolidinethione, 1-decyl-4,4-dimethyl-2-irnidazolidinethione, l-isopropyl-4,4-di1nethy-l 2 imi-dazolidinethione, l-octadecyl-4,4-dimethyl 2 imidazolidinethion, l-hexadecyl-4,4-dimethyl 2 imidazolidinethione, 1-benzyl-4,4- dimethyl-Z-imidazolidinethi0ne, 1-cyclohexyl-4,4-dimethyl-Z-imidazolidinethione, etc.

In accordance with my invention, the above-described substituted imidazolidinethiones can be added to the desired lubricant in amounts of from about 0.1 to 10% by weight. However, I preferto use from about 0.5 to 2%. by Weight of the substituted imidazolidinethiones of my invention.

The corrosiveness of the lubricant can be tested by means of various devices. One of these devices is the Underwood oxidation test apparatus.

The Underwood oxidation test apparatus comprises essentially an oil sump containing an electric heater, a gear pump driven by a /3 horsepower electric motor, a tube containing four orifices, a connecting means connecting the oil sump and the tube, a 30 mesh Wire screen positioned between the orifices and the oil sump, and a rectangular box containing all of the aforementioned, except the connecting means and the gear pump. The apparatus is fitted with several control attachments, such as an adjustable thermostatic control attached to a thermocouple for maintaining the desired temperature of the oil, a pressure gauge, a by-pass valve for adjustment to the desired pressure and a control switch for the electric immersion heaters.

The Underwood oxidation test is conducted by charging the desired amount of the test oil containing a suitable oxidation accelerator into the apparatus, placing two copper-lead. bearings backed with a copper strip in position opposite the orifices, starting the pump and regulating the temperature and pressure. The test can be conducted for any prescribed length of time after which the bearings are cleaned and weighed. By calculating the loss in weight of the bearings the amount of corrosion produced by a lubricating composition containing an oxidation accelerator can be compared to the amount of corrosion produced by a lubricating composition tested under the same conditions containing an oxidation accelerator and a corrosion inhibitor.

The oil base which can be used to prepare the noncorrosive lubricating compositions of my invention is preferably a liquid hydrocarbon lubricating oil which will not readily decompose over extended periods of time. The hydrocarbon oil used in preparing the non-corrosive lubricants of my invention can also contain constituents to improve the pour point, etc. Materials used in the art for these purposes which are compatible with the hydrocarbon oil will be found to be useful in the non-corrosive lubricant of my invention.

The following examples are set out to illustrate my invention. 'It is not intended that the invention be limited to the materials, procedures and proportions set out therein. Various equivalents of my invention will obviously occur to those skilled in the art and I intend to include such equivalents within the scope of my invention.

Example I 2500 milliliters of test lubricant containing Kendall SAE No. oil and 0.01% by weight Fe O as iron naphthenate was charged to the Underwood apparatus. Two previously weighed copper-lead bearings were fixed into position opposite the orifices. The heaters were turned to a temperature of 325 F. and the pressure was regulated at 10 p.s.i. The test was continued for 10 hours, after which the balls werecleaned by a special solvent consisting of equal parts of denatured alcohol, toluene and ethyl acetate and Weighed to determine the weight loss due to corrosion. The table below shows the results of the test and shows the amount of corrosion produced by the lubricating composition containing an oxidation accelerator.

Test 1 Test 2 Weight of bearing before test/gins. 41. 9021 41. 9520 Weight of bearing after test/grns. 41. 7585 41. 8063 Weight loss 0. 1436 0. 1457 Percent weight loss 0.342 0. 347

Example II 2500 milliliters of test lubricant containing Kendall SAE No. 10 oil, 0.01% by weight Fe O as iron naphthenate and 1% by weight 1-isopropyl-4,4-dimethyl-Z- imidazolidinethione was tested as described in Example I.

The table below shows the results of the test and shows the amount of corrosion produced by a lubricating composition containing an oxidation accelerator and a corrosion inhibitor.

Test 1 Test 2 Weight of bearing before test/gins 41. 7504 42. 1506 Weight of bearing after test/gms 41. 6667 42. 0631 Weight loss 0. 0837 0. 0875 Percent weight loss 0. 200 0. 207

Example 111 p 2500 milliliters of test lubricant comprising Kendall 'SAE No. 10 oil, 0.01% by weight Fe o as iron naphthenate and 2% by weight 1-benzyl-4,4-dimethyl-Z-imidazolidinethione was tested as described in Example I. The table below shows the results of the test and shows the amount of corrosion produced by a lubricating com.- position containing an oxidation accelerator and a corrosion inhibitor.

Test 1 Test 2 Weight of bearing before test/gms 42. 4507 42. 4794 Weight of bearing after test/gins"-.. 42. 4102 42. 4494 Weight loss 0. 0405 0. 0300 Weight loss, percent 0.093 0.073

Example IV 2500 milliliters of test lubricant comprising Kendall SAE No. 10 oil, 0.01% by weight Fe O as iron naphthenate and 1% by weight 1-decyl-4,4-dimethyl-Z-irnidazolidinethione was tested as described in Example I. The table below shows the results of the test and shows the amount of corrosion produced by a lubricating composition containing an oxidation accelerator and a corrosion inhibitor.

Test 1 Test 2 Weight of bearing before test/gins 42. 2293 42. 4741 Weight of bearing after test/gins 42. 1604 42. 4123 Weight loss 0. 0629 0. 0018 Percent weight loss .l 0. 149 0.

Example V 2500 milliliters of test lubricant comprising Kendall SAE No. 10 oil, 0.01% by weight F6 0 as iron naphthenate and 1% by weight l-heXadecyl-4,4-d-imethyl-2- imidazolidinethione was tested as described in Example I. The table below shows the results of the test and shows the amount of corrosion produced by a lubricating composition containing an oxidation accelerator and a corrosion inhibitor.

Test 1 Test 2 Weight olbearing before test/gins. 42.1039 42. 4836 Weight of bearing alter test/gins 42. 0846 42. 4064 Wei ht loss 0. 0193 0. 0172 Weight loss, percent 0. 046 0.040

Example VI 2,500 mls. of test lubricant containing Kendall SAE No. 10 oil, l-(hydroxy-t-butyl) 4,4 dimethyl-Z-imidaz- .olidinethione (1% by weight) and Fe 0 as iron naphthenate (0.01% by weight) were charged to the Underwood apparatus. The Underwood oxidation test was performed as described in Example III. The table below shows the results of the test and shows the amount of corrosion produced by a lubricating composition containing an oxidation accelerator and 1% by weight l-(hydroxy-t-butyl -4,4-dimethyl-2-imidazolidinethione.

Test 1 Test 2 Weight of bearing before test/gins 42. 4002 42. 7487 Weight of bearing after test/gms 42. 3984 42. 7364 Weight loss 0.0108 0.0118

Weight loss, percent 0.023 0. 028

Now having described my invention, what I claim is: '1. A non-corrosive lubricating composition consisting essentially of a hydrocarbon lubricating oil and from about 0.01 to about 10% by weight of a substituted imidazolidinethione having the following structural formula I l CHI-(1] (ll-C Ha R-N N-H where R is a member selected from the group consisting V References Citezi in the file of this patent UNITED STATES PATENTS Morton June 24, 1930 Martin Apr. 11, 1939 Loane et al. July 30, 1940 Nelson et al. Jan. 1, 1952 Roussel June 19, 1956 Hughes Jan. 13, 1959 Buxbaum July 12, 1960 

1. A NON-CORROSIVE LUBRICATING COMPOSITION CONSISTING ESSENTIALLY OF A HYDROCARBON LUBRICATING OIL AND FROM ABOUT 0.01 TO ABOUT 10% BY WEIGHT OF A SUBSTITUTED IMIDAZOLIDINETHIONE HAVING THE FOLLOWING STRUCTURAL FORMULA 